You can import Ralf's Tamil dictionary (version 0.1; GPLv3) into simon. Training with this dictionary is not possible.
The <phoneme> elements contain eSpeak phonemes (not IPA phonemes) – alphabet="espeak".
You can try to record Tamil words with simon:
It is necessary to do further adjustments. This is just a first step to make simon work with the Tamil language.
If your native language is Tamil, you may want to do the following things:
1. Install simon.
2. Install HTK.
3. Import Ralf's Tamil dictionary into simon.
4. Record some Tamil words with simon (see screen-shot).
After you have done that, you can try to improve Ralf's Tamil dictionary.